Currently blkdev_issue_discard() doesn't check that submitted discard
request matches granularity required by the underlying device.
Submitting such requests to the device can have unexpected consequences
(e.g. brd driver just discards more / less data depending on how exactly
the request is aligned). So test that submitted discard request has the
granularity required by the driver.
Signed-off-by: Jan Kara <jack@xxxxxxxx>
---
block/blk-lib.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/block/blk-lib.c b/block/blk-lib.c
index bd40292e5009..7170d02e9e9a 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -61,6 +61,13 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
if (!blk_queue_discard(q))
return -EOPNOTSUPP;
+ if (q->limits.discard_granularity) {
+ unsigned int gran_sect = q->limits.discard_granularity >> 9;
+
+ if (sector % gran_sect || nr_sects % gran_sect)
+ return -EINVAL;
+ }
+
if (flags & BLKDEV_DISCARD_SECURE) {
if (!blk_queue_secdiscard(q))
return -EOPNOTSUPP;
--
2.1.4
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